Such slide-ring seals, that can also be designed as slide-ring seals for a housing, are generally known in the state of the art for sealing a stationary element against a rotating element, customarily a shaft. A typical area of application is for pumps that move a liquid. A slide-ring seal is used e.g. at the position where the shaft is to be sealed relative to the pump housing in order to drive a pump impeller in contact with a liquid to be transported. Accordingly, there is always a side in contact with a transport medium in a slide-ring seal.
Slide-ring seals are customarily designed in such a manner that a so-called counter-ring is rotationally fixed and especially sealed to a rotary shaft. This forms a seal between the shaft and this counter-ring e.g. by at least one annular seal ring fitted to the counter-ring.
Such a counter-ring can be arranged between two so-called slide rings of which one slide ring makes contact with the counter-ring via a slide surface. This slide surface makes a sealed contact of the slide ring on the counter-ring possible and at the same time permits rotation of these elements relative to one another. The selection of the material for these rings must be made accordingly. Usually, silicon carbide is selected as the material for the slide rings and also for the counter-rings, which material has excellent running properties but has the disadvantage of being very brittle and therefore subject to fracture.
Thus, there is usually a leakage problem in such slide-ring seals in the region of a seal ring that should ensure the seal between counter-ring and shaft, or, in the case of the rings consisting of a very brittle and therefore breakable material such as for example silicon carbide.
If for example a seal ring on the counter-ring is defective, liquid can pass the slide-ring seal axially on the shaft and enter e.g. into the motor compartment of a pump, where it results in damage even before such a leak is discovered. Furthermore, even fracture of one of the rings, especially of the counter-ring or of a ring inserted in it and consisting e.g. of silicon carbide can result in a leak in which liquid can penetrate through a slide-ring seal.
Rings, especially if they are manufactured from a very brittle material such as e.g. silicon carbide can break on account of canting or also by in particular localized stress, especially when a motor is started e.g. when the rings run into a stop opposite a housing in order to ensure that the unit consisting of slide rings and surrounding housing rotates jointly relative to the counter-ring. High localized stresses of the ring material and therefore also damage to the material can occur particularly in the region of these rotation blockers.
The invention has the object of providing a new-design slide-ring seal, in particular a slide-ring seal for a housing, that makes it possible to detect a leak even before the fluid can pass from a medium side to the dry side where it can cause damage, and/or to prevent a leak, and which preferably has a lower susceptibility in particular to material breakage.